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# frozen_string_literal: true
require 'monitor'
module Faraday
# Adds the ability for other modules to register and lookup
# middleware classes.
module MiddlewareRegistry
def registered_middleware
@registered_middleware ||= {}
end
# Register middleware class(es) on the current module.
#
# @param mappings [Hash] Middleware mappings from a lookup symbol to a middleware class.
# @return [void]
#
# @example Lookup by a constant
#
# module Faraday
# class Whatever < Middleware
# # Middleware looked up by :foo returns Faraday::Whatever::Foo.
# register_middleware(foo: Whatever)
# end
# end
def register_middleware(**mappings)
middleware_mutex do
registered_middleware.update(mappings)
end
end
# Unregister a previously registered middleware class.
#
# @param key [Symbol] key for the registered middleware.
def unregister_middleware(key)
registered_middleware.delete(key)
end
# Lookup middleware class with a registered Symbol shortcut.
#
# @param key [Symbol] key for the registered middleware.
# @return [Class] a middleware Class.
# @raise [Faraday::Error] if given key is not registered
#
# @example
#
# module Faraday
# class Whatever < Middleware
# register_middleware(foo: Whatever)
# end
# end
#
# Faraday::Middleware.lookup_middleware(:foo)
# # => Faraday::Whatever
def lookup_middleware(key)
load_middleware(key) ||
raise(Faraday::Error, "#{key.inspect} is not registered on #{self}")
end
private
def middleware_mutex(&block)
@middleware_mutex ||= Monitor.new
@middleware_mutex.synchronize(&block)
end
def load_middleware(key)
value = registered_middleware[key]
case value
when Module
value
when Symbol, String
middleware_mutex do
@registered_middleware[key] = const_get(value)
end
when Proc
middleware_mutex do
@registered_middleware[key] = value.call
end
end
end
end
end
|
